the cold water was leaving or warmer water was entering the borehole through

horizontal fractures or solution features at these elevations. Slight

increases in borehole diameter occur at these same elevations, and also at

other elevations where temperature changes were not observed. The gamma log

shows much variation over short vertical distances, suggesting small-scale

variability in lithology. Highest gamma values generally should coincide with

zones of clay or other fine-grained material. The log suggests the presence of

thin zones of clay at elevations of approximately 700, 660, and 580 ft; these

zones may be horizontal fractures filled with fine-grained material washed down

from the surface.   Television logs confirm the presence of these fracture

zones. The SP and resistivity logs can be easily correlated between boreholes

at the site, and appear to be related more to lithologic changes than to

fracture locations.



Vertical Distribution of Hydraulic Head



     Vertical hydraulic gradients at the monitoring site are steeply downward.

 Vertical gradients are much greater than horizontal gradients, suggesting that

 the aquifer is highly anisotropic. Figure 7 shows the distribution of total

 hydraulic head in the subsurface in July 1987. The water table at the site is

 at an elevation of about 780 ft, or about 20 ft (6 m) below the land surface,

 as shown by the heads in shallow piezometers MW5A and MW5B. The continuous
 presence of water in these piezometers was Unexpected on the basis of previous

 research (Sherrill, 1978; Bradbury, 1982), which placed the water table in the

 area about 150 ft (46 m) below the ].and surface. Below the water table,

 hydraulic heads decrease significantly with depth. A change in the vertical